Humanity faces an alarming paradox: we have never had so much technical knowledge or so many resources available, and yet we are heading toward a global deficit of 40% of freshwater by 2030. In East Africa, Kenya exemplifies this crisis: more than 40% of its population lacks access to safe water, forcing millions of people to rely on unsafe sources. Schools suspend classes due to lack of water, hospitals are forced to operate under high risk of infections, and communities absorb extra costs that perpetuate vulnerability.
In response to this scenario, the Solar Powered Water Harvesting project proposes a bold solution: transforming school and hospital rooftops into self-sufficient water plants through the combination of rainwater harvesting and solar pumping, with full treatment (filtration, UV, and chlorination). This intervention not only guarantees continuous and high-quality water, but also redefines how vulnerable communities can ensure their human right to water. With an investment of USD 500,500, it will generate 22.8 million liters per year, a volume comparable to the domestic consumption of more than 8,000 households or enough to cover 60% of the water needs of an average school of 500 students.
The strategic justification is twofold: in the short term, to solve the lack of safe water in critical institutions; in the structural sense, to demonstrate that it is possible to move from a model of scarcity and dependence to one of community and climate water resilience. The project is located in Vihiga County, Kenya, within the Lake Victoria basin, a region of high population density and water stress. Key actors include technical developers, school and health committees, local authorities, and external verifiers. The entire model is aligned with the Water Positive roadmap, complying with the principles of intentionality, additionality, and traceability under VWBA 2.0 and WASH-BA, ensuring that every liter generated is measurable, verifiable, and auditable as a tangible water benefit.
The current situation in Vihiga reflects a complex structural challenge: schools rely on contaminated or intermittent sources, hospitals cannot guarantee safe water for critical processes such as sterilization and maternal care, and thousands of children and women must walk long distances to collect water, exposing themselves to safety risks and loss of productive hours. This scenario generates low educational efficiency, high health risks, and hidden costs that limit community development.
In response, the project proposes a decisive technical and strategic opportunity: implementing solar-powered rainwater collection, purification, and distribution systems that ensure continuity of supply, reduce emissions, and eliminate dependence on fossil fuels or water trucks.
The volume transformed is significant: 22.8 million liters of safe water per year, equivalent to filling more than 9 Olympic-size swimming pools or the annual consumption of 8,000 households, a volume capable of supplying 20,000 people and improving hygiene in health centers and school continuity.
The immediate benefits are compelling: reduction of diarrheal and hospital-related diseases, reduced school absenteeism, improved hospital efficiency, and strengthened corporate reputation for partners. In the medium term, savings in medical expenses and improvements in educational and labor productivity are expected. In the long term, the project contributes to the climate resilience of the basin and the sustained reduction of pressure on aquifers.
The initiative is made possible thanks to the collaboration of specialized technical developers, local operators, community committees, county authorities, and strategic partners that ensure traceability and governance. Its replicability is guaranteed because the model is modular, scalable, and applicable in contexts of high rainfall and deficient water infrastructure. Acting now is crucial: the costs of non-intervention will continue to rise in terms of public health, education, and climate resilience. Companies with ambitious ESG commitments, in sectors such as food, retail, energy, or health, can lead this solution and gain reputational benefits, competitive differentiation, international visibility, and alignment with global sustainability standards.
The proposed technical solution integrates green infrastructure, renewable energy, and digital tools. Roofs of 300–1,000 m² serve as rainwater collection surfaces that channel water into cisterns with a capacity of up to 1.52 million liters per site per year. This water undergoes a treatment train consisting of multilayer filtration, UV disinfection, and residual chlorine dosing, ensuring compliance with WHO quality standards. The resource is then pumped through photovoltaic solar energy into elevated tanks that ensure pressure and continuous distribution. The choice of this technological combination responds to criteria of efficiency, low OPEX, robustness in rural contexts, and alignment with principles of sustainability and replicability.
Alternatives such as conventional treatment systems dependent on electricity or diesel, and groundwater wells, were evaluated but discarded due to high operating costs, contamination risks, and dependence on overexploited aquifers. The solar-rain hybrid model was selected for its resilience, modularity, and ability to scale in different communities. Its operational capacity allows it to supply 22.8 million liters annually, sufficient to serve more than 20,000 users in critical institutions.
Regarding risks, potential technological failures in pumps or UV lamps, hydrological variability associated with changes in rainfall patterns, limited social acceptance in early stages, and contamination risks due to lack of maintenance were identified. Mitigation measures include redundancy in critical components, contingency plans ensuring minimum safety storage, shared governance protocols with community committees, and local technical training to ensure continuous operation. Climate resilience is secured through cistern sizing for droughts, diversification of sources (rainwater supplemented with network or truck water in contingencies), and digital monitoring of flows and quality.
The expected benefits are quantifiable: 22.8 million liters per year of safe water (VWBA A-3 and A-6), emissions reduction by replacing diesel with solar energy, reduced pressure on aquifers, and improvements in public health, gender equity, and school productivity. In addition, investing companies gain economic benefits (reduced costs associated with interruptions and water transport), reputational benefits (ESG compliance and international visibility), and strategic benefits (competitive differentiation and alignment with the Water Positive agenda under the principles of intentionality, additionality, and traceability). Finally, the solution is scalable to other counties in Kenya and regions of Sub-Saharan Africa with conditions of high rainfall, favorable regulations, and organized communities, ensuring replicability and sustained expansion potential.
Implementation is conceived as a phased, technical, and adaptive process, designed to maximize impact and ensure the permanence of benefits. In Phase 1 (Diagnosis and Design, 0–3 months), the hydrological and social baseline will be established: quantity and quality of available water, rainfall patterns, captured flows, and institutional demand. Laboratory analyses, topographic surveys, and user surveys will be conducted to size the system. Reference indicators will include turbidity, presence of coliforms, hours of water availability, and costs associated with external supply.
Phase 2 (Execution, 4–9 months) will cover the installation of collection roofs, gutters, cisterns, multilayer filters, UV lamps, automatic chlorine dosers, photovoltaic solar modules, and elevated tanks. Each site will be designed with a nominal capacity of 0.5 to 2.0 m³/h, ensuring an annual yield of up to 1.52 million liters per unit. This technology was chosen for its low OPEX, robustness in rural areas, and compatibility with WHO standards. Control instruments include flow meters, level sensors, UV intensity alarms, and chlorine residual probes, all connected to an IoT platform with GSM/LoRa telemetry.
In Phase 3 (Commissioning and Validation, 10–12 months), hydraulic and microbiological performance tests will be conducted, external audits under VWBA, and verification of WASH-BA indicators. Liters captured, treated, and distributed (A-3, A-6), number of beneficiaries, and reduction of reported diseases will be measured. Monitoring frequency will be monthly for quality parameters, daily for flows, and continuous for operational alarms. Physical traceability will be ensured through closed flows from collection to points of use, and digital traceability through the IoT platform that generates automatic reports and alarms in case of deviations.
Phase 4 (Continuous Operation and Improvement, 12+ months) will be based on community governance protocols, with differentiated roles: technical operators for preventive maintenance (cleaning gutters, filter replacement, doser calibration), local committees responsible for water use, and external verifiers who will audit annual results. Contingency plans will be applied for droughts and critical failures, with redundancy of key components and minimum safety storage. The system will operate under a continuous improvement logic, comparing with-project versus without-project scenarios, adjusting processes based on data feedback, and updating technologies as necessary. This approach ensures long-term resilience to climate change and permanence of benefits in health, education, and water resilience.
The Solar Powered Water Harvesting project in Vihiga is a comprehensive intervention that combines technological innovation, social impact, and strategic value. Technically, the main action is rainwater harvesting with purification and photovoltaic solar pumping, applied to school and hospital rooftops transformed into reliable sources of drinking water. The process includes several stages: rainwater collection on surfaces of 300–1,000 m², conduction to cisterns, multilayer filtration, UV disinfection, and residual chlorination, solar pumping with a nominal capacity of 0.5–2.0 m³/h, and distribution through elevated tanks to points of consumption. The entire system has been designed under WHO quality standards, Kenyan regulations, and international WASH safety guidelines.
The relevance of the solution lies in its response to a structural problem: educational and health communities with intermittent services, exposure to contaminated sources, and high costs from water hauling. Compared to this baseline, schools closed due to lack of water, recurrent hospital infections, hours lost in manual collection, the intervention offers a radical change: continuous availability, certified water, and energy autonomy. It is the most suitable option for this context because it leverages the high rainfall of the Lake Victoria basin, avoids overexploitation of aquifers, and adapts to a social environment with active community committees.
The expected results are measurable: 22.8 million liters of safe water per year, verifiable reduction of microbiological contaminants, decline in waterborne diseases, lower CO₂ emissions by replacing diesel, and improvements in public health, school attendance, and food security. Additional benefits include gender equity (by freeing girls from the burden of fetching water), local capacity building, and strengthening of community resilience.
Strategically, the project is integrated into the Water Positive roadmap, contributing verifiable volumes under VWBA (A-3, A-6) and meeting principles of intentionality, additionality, and traceability. For investing companies, it represents a social license to operate, strengthened reputation, regulatory compliance, and competitive differentiation in an increasingly ESG-demanding market. It also aligns with global commitments such as SBTi, the NPWI initiative, and the ESRS E3 framework, reinforcing its value in corporate reporting.
Replicability is assured: this modular, low-OPEX model can be applied in other counties of Kenya and Sub-Saharan Africa with high rainfall and critical water needs. Its scalability is facilitated by partnerships among local operators, governments, and private actors that ensure financial and technical sustainability.
The expected final impact is profound: contribution to the water balance of the basin by reducing pressure on overexploited wells, increased resilience to droughts, generation of local jobs and capacities, improved health and water access for thousands of people. The message to investors, clients, and society is clear: this initiative demonstrates how a well-designed project can lead the transition to a regenerative economy, where every liter harvested and treated becomes an opportunity for human and environmental development.
